


Demon Included

by CielPansyhive



Series: House Demon AU [1]
Category: Kuroshitsuji | Black Butler
Genre: Adult Ciel Phantomhive, Alois barely mentioned, Alternate Universe - Modern Setting, Anxiety Attacks, Blood and Injury, Demon Sebastian, No Smut, SebaCiel - Freeform, Sebastian is a big dumb demon, Sick Ciel, house demon au, not really sebaciel in this fic but eventual in this AU, poor Ciel is afriad of his own shadow
Language: English
Status: Completed
Published: 2018-12-29
Updated: 2018-12-29
Packaged: 2019-09-29 15:04:19
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 4,289
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17205623
Author URL: https://archiveofourown.org/users/CielPansyhive/pseuds/CielPansyhive
Summary: If something seems too good to be true, it probably is. Ciel just bought his first house and it was a steal! He assumed it was dirt cheap because of the wear and tear, not because it came with a demon.Sebastian finally has some company in his domain! It's been years since he interacted with a human, such fascinating creatures!(Yes, this is the first installment of the House Demon AU)





	Demon Included

**Author's Note:**

> Thanks for waiting so patiently guys! This was originally for SebacielSummerWeek (cliches 5 times + 1 time) 5 times Sebastian tried to be helpful + 1 time he actually helped. I was then going to re-purpose it for SebacielHalloweenWeek (haunted places). This has been one paragraph away from being finished for MONTHS! Sorry it took me forever to finish, I hope it was worth the wait. Please leave kudos and comments!
> 
> Feel free to follow me on my accounts:  
> https://cielpansyhive.tumblr.com  
> https://twitter.com/CielPansyhive

Sebastian leaned his head against his hand as he stared out the window, bored to death. He lost count how many years he had been alone. The last residents hadn’t even bothered to put the house up for sale. They just packed up and ran. _How disappointing._ He gazed at the eggshell painted walls. _Boring,_ he yawned. The brightest colored thing in the house was a slate grey couch that the last family left behind. _No taste, no character, this place is so utterly dull._ He sighed and tapped an onyx hoof on the creaky hardwood floor. He was about to aimlessly wander about the house, as he did most days, when his pointed ears perked up. _That sounded like a car! A car stopping out front!_ He couldn’t stop the grin from spreading across his face, multiple rows of pointed teeth glistening. He peered down at the street to see a car indeed parked in front of the house. _A new resident? At this point I’d settle for a little old lady! Anyone!_ His strong but thin, spear tipped tail thrashed around like an ecstatic puppy. His tail hit an end table in his excitement, splintering it. He looked over at the broken pieces. _I’ll fix that later._ When he looked back to the street he saw a small figure emerge from the car. A young man, maybe early 20’s, with a mop of navy blue hair struggling with his rolling luggage and duffle bag. _Fascinating! Finally some interesting company!_ He retreated back into the shadows, his body molding and becoming one with them. _I can’t wait for our first interaction, little one._

Ciel huffed as he lugged his bag up the cracked, uneven stairs. He fished for his key in his blazer pocket.

“Come on where is it?” he grumbled as the door clicked and opened by itself. He popped his head in and looked around confused. “Um, hello?” he set his bags by the door and crept into the living room. “Hello? Is someone here?” He walked into a large spider web that covered half the doorframe. “Yuck! This place is a mess!” he spat and shook the cobwebs from his hair. He flailed his arms and bumped into the couch pitching his body forward. A cloud of dust shot up when he landed. He coughed into his hand, lungs already burning. “Apparently no one who’s lived here has ever heard of upkeep.” He hacked and sat up. “At least it’s furnished as advertised,” he covered his mouth and headed towards the front door. “I guess I’ll spend my first night cleaning, ugh what a mess.” He slammed the door behind him, muttering obscenities under his breath.

1.

When the loud roar of an engine was heard Sebastian stepped out from the shadows of the hallway. _It seems he gets rather ill from dust. I can’t let that happen, he just got here. I’ll clean for him! By the time he’s back this house will be spotless!_ Sebastian cheerfully ran around the room, swiping his claws at the webbing. He cracked open a window and let the stale air move. He inhaled as much dust as he could and breathed it back out through the window, making thick grey dust clouds. He continued to do so until he could no longer spot a single particle of dust. His throat tickled and he let out a weak cough. _Hmm, I do see how dust could be bothersome. I must remember to not let it get out of hand again, especially for my young human’s sake._ He sauntered into the bathroom and got to work on the tiles. He used his claws to dig any dirt out from the grout. He next scraped off any rust from the faucet, the shiny silver broke through. He went to each room, making sure it was perfect for his new human. When he was finished he had a smug look on his face. _The human will be so pleased! I do hope he comes back soon!_ He eagerly waited crouched in the shadow of the staircase. When Ciel returned he had his mouth and nose covered with a mask, a broom under his arm, and bags filled with sponges and chemicals. He let everything drop as soon as the living room was in sight. Sebastian chuckled softly, _Ah! Human was surprised! Now he doesn’t have to do any work! You are very welcome._ His joyful mood was cut short when Ciel’s eyes widened and he started hyperventilating.

“What the fuck is going on?” Ciel bolted into each spotless room, searching for the intruder that had kindly let him in earlier and had cleansed his house while he was away. “Where are you? I know I’m not alone in here! I’ll-I’ll call the cops if you don’t come out!” his voice trembled. He ripped open every closet door and cabinet to be sure he was alone. For an entire hour he just ran back and forth shouting, banging on walls, looking over his shoulder with wild eyes. Though Sebastian found it quite entertaining he did not like the obvious emotional stress this was causing his human. He sighed and folded his long arms. _I was only doing you a favor; you could be a little more grateful._ He pouted and stayed out of the way while his little human had a fit. That night Ciel sat up in bed and clutched his cell phone to his chest. Next to him he had set a heavy bookend, a giant solid black knight chess piece, the only thing he had close to a weapon. He jumped at every groan and creak of the old house. He didn’t dare slumber.

2.

It had been a week since Ciel moved in. Sebastian continued to watch from the shadows, learning all he could about his new roommate. He found that Ciel loved to read in his spare time. Also that Ciel read books not only in English but also in French, German, and Spanish. _Smart boy!_ _I have some books in the cellar that no human has ever had the pleasure of reading. He’d love them!_ He only solidified his body when Ciel was away, not wanting to frighten the human away with his form. He pulled out a locked trunk from a hidden hatch in the cellar. There were few material items he desired to keep, but those he did were in the trunk. He held the ancient texts in his clawed hands. _Such memories, I’m glad I was able to at least summon these to this realm. Even though I can’t seem to leave this place myself._ He flipped the gold edged pages, scanning over the Latin words. He carried them back into Ciel’s room and set them on the night stand. When Ciel arrived home he was exhausted, he yawned and pawed at his tired eyes. He was too tired to even attempt to make dinner and instead headed straight to his room to sleep. He flopped on his belly onto the bed and blindly tried to place his phone on the end table. His hand met with the old books, he turned to look, confusion clear on his face.

“What are these?” he sat up and glared at the strange books. “These aren’t mine…and they certainly weren’t here earlier…” he picked one up and flipped through the pages. “What the hell?” his eyes widened at the Latin words and reddish brown stains covering some pages. He quickly slammed the book and searched the room. Nothing else seemed out of place, but somehow these books appeared in his room. “These must have belonged to the previous owner. Maybe I _did_ set them here and forgot about it when I was moving their stuff out. Yeah, I’m sure that’s all, haha me and my goldfish memory,” he couldn’t suppress the shiver that shot up his spine. He tucked himself in bed and tried to ignore the nagging feeling at the back of his mind that he needed to leave. Leave now.

3.

Ciel tossed and turned in his sleep unable to get comfortable. He whimpered and moaned, scratching at his irritated skin. Little red bumps littered his skin. Sebastian peered down at his little human. _How dare those bugs feast on my human, sucking the red nectar from his vessel! I will hunt down every single beast that has harmed him and I will make them suffer! I will tear each leg off slowly; crush their wings between my claws!_ Ciel flipped onto his stomach, his naked back revealed even more bites marring his porcelain skin. _No, this will not do. He needs his sleep, how can he stay asleep if he keeps scratching?_ Sebastian gently rested his large hand on Ciel. His hand covered from Ciel’s lower back to his delicate shoulder blades. Ebony starkly contrasted with the flushed bites, pin pricks of crimson dotted a few bumps from being rubbed too hard. _I’ll help relieve him! He won’t wake up to scratch at himself if I just scratch for him!_ Sebastian smiled, so proud he found a solution. He lightly scratched at Ciel’s back, puzzled when he drew his hand back, to see long gashes oozing blood. Sebastian frantically tried to soothe the damage by rubbing his hand over the skin, only for his claws to catch on the jagged lifted skin. Ciel made a pained sound as he started to rouse from sleep. Blood smeared all over Ciel’s back and dripped onto the pristine white sheets. Sebastian stepped back into the shadows, frustrated that he caused yet more discomfort to his human. _I just…I just wanted to help. I didn’t mean to!_ Ciel’s long lashes fluttered as he woke. He gave a shout as he felt the sharp pain in his back. He brought a hand to his back and felt the sticky blood cake onto his hand. He tried to get up but it hurt too much. He pulled his phone off the end table, dialed his best friend, and put it on speaker. It rang five times before someone picked up.

“Yo, Ciel it’s like,” he yawned obnoxiously, “four in the morning.”

“A-Alois, please just-just get here!” tears stung his eyes. “I need help!”

“Whoa, whoa okay I’m on my way! What happened? Never mind, you tell me when I get there. I’m leaving right now!” he hung up leaving Ciel in the deafening silence. He cried into his pillow, scared out of his mind but unable to do anything. Sebastian watched on, furious with himself. _How could I have been so stupid? Humans are so fragile._ Alois took only ten minutes to get there. He used his spare key to unlock the door, “Where are you?”

“Bedroom!” Ciel used all his strength to yell. Alois stomped up the stairs and into the room. Alois flipped on the light and screamed.

“What happened? Dude, your back is seriously fucked up!” Ciel tried to turn his head to see, all he saw was red.

“It hurts! What does it look like?” Alois stepped closer.

“It’s like, scratches, but deep…it looks like someone took a rake to your back!”

“The fuck?”

“You don’t know how you got these?” Ciel shook his head no. “Okay, uh, let’s get you to the 24 hour clinic.” Alois helped Ciel to sit up and walked him to his car.

Ciel had the nurse clean, stitch, and bandage his wounds. Fifteen lacerations, they told him. He stayed as Alois’s apartment for the next few days. He had a lot of courage to work up to go back to his house. Meanwhile Sebastian’s guilt ate away at him every day the human didn’t return.

4.

Ciel had finally installed security cameras all over the house. He found himself constantly looking over his shoulder, fearing the worst. Ever since his ‘attack’ he feared waking up with more scratches. So far nothing like that happened again, but he still felt an unexplainable presence in the house. Nothing ever went missing, if anything he found gifts randomly around the house. One morning he found an elegant, antique pocket watch placed in his jacket. Another morning he found a small bouquet of flowers, the same color as his eyes, on his bedroom windowsill. It still sent a chill up his spine. He was lucky if he slept a couple hours a night, terrified to shut his eyes for any longer. He consumed so much caffeine he couldn’t stop his body from shaking. At times his heart skipped beats and he felt like he was going to faint, but he dare not sleep anymore than absolutely necessary. Dark violet circles under his eyes stood out against his pale almost ashen skin. The clothes that were tailored specifically for him now hung loose on his tiny body. The stress he endured the past few months weighed heavy on him. Sebastian didn’t like this at all; his human was fading away and was beyond paranoid. When Ciel was away from the house he couldn’t keep his eye on him. This irked the demon. What good were his demonic abilities if he couldn’t protect his human when he was away? He called upon as many crows he could summon. They all gathered in the backyard, away from where Ciel would be watching.

“Listen, my new resident, Ciel, needs to be looked after. I fear for his health and safety. As you know, I am bound to this god forsaken house,” he grumbled and stomped his hoof. “Please protect him for me when he is not here.” The crows squawked their agreement and set out to their posts. Sebastian felt a little more relieved knowing he’d have many eyes on Ciel.

“Shoo! Go away!” Ciel batted at a large crow sitting on the roof of his car. “I have to go to work!” The crow stared at him, not budging an inch. Ciel sighed and opened the car door. “You want to go for a ride? Fine! Stupid bird brain.” He slammed the door and drove off. The whole drive he heard the crow’s feet scampering and sliding around on the roof of the car. If that wasn’t odd enough he swore he saw another crow in the rearview mirror following him. “Demented birds,” he huffed. He parked in his usual spot and sat there. His stomach growled, he knew he should have had breakfast but his nerves made him feel too nauseated. He sighed and stepped out of the vehicle, as he stood up his vision temporarily clouded over and his knees threatened to buckle. He gripped onto the car and waited for his vision to return. After a few seconds he could see again and he was fairly certain he wasn’t seeing double. However, now there were two crows sat on the roof. “What the hell?” he didn’t have time to worry about it. He walked into his work building and checked the schedule. _Ugh stocking? I guess it’s okay, I don’t have to deal with customers._ He grabbed a palette jack and started stacking boxes of merchandise on it. It took more strength than usual to pull the palette, by the time he was in front of the correct shelves he was out of breath. He set up the ladder and secured it. His heart was pounding hard in his chest in time with the blooming headache. He grabbed some items and shakily made his way to the top step. He was met with a large crow, squawking at him on the top shelf. He nearly fell backwards off the ladder. “GO!” he tossed what he had in his hand at the bird. His breath caught in his throat, one of his hands instinctively clawed at his shirt like the collar was the problem. He coughed and wheezed as he slowly descended the steps. Once his foot firmly planted on the floor he toppled backwards, clutching is chest. He swore his heart stopped, everything started to fade black, and he couldn’t get a proper breath of air.

“Ciel! Aye, what’s going on? Are you alright?” one of his coworkers shouted, though he could barely hear it over the roar in his ears. His head thumped onto the floor and he was out cold.

Ciel woke up to the sound of erratic beeping and voices. He opened his eyes, he was in a hospital. A nurse was injecting something into an IV and a doctor hovered over him with a clipboard.

“How nice of you to join us,” the doctor smiled. “Your work called emergency services; apparently you fainted and hit your head. We just need to make sure you don’t have a concussion, you were out for a long time.” Ciel blinked trying to take in all the information. “Your heart rate isn’t where we like it to be, do you usually have a fast heart rate?”

“I-I don’t think so?” Ciel mumbled.

“Okay, we’ll have to look into that as well, we gave you something to slow it down. You really need to follow up with your doctor after we release you okay?”

“Okay,” Ciel looked at the monitor. _Is it really almost at 200? Is that even possible?_

“No caffeine intake until your doctor clears you, okay?” Ciel nodded. _Tell the crows not to scare the shit out of me while you’re at it. What the hell is with them anyways? I’ve never seen so many of them around here._

Sebastian had a stern discussion with his crows when he got news that one of them sent Ciel to the hospital. He knew it wasn’t completely their fault, but he thought they would have been a bit more discreet in their stalking.

5.

Ciel was tucked into his bed, slipping in and out of consciousness. His health just continued to decline after his hospital visit. His heart rate was more normal, since his break from caffeine, but his immune system was still weakened. His sleep was interrupted every time he started choking, his airways raw and irritated. Sweat soaked, cobalt hair was matted to his forehead. His high fever made the silk sheets feel like sandpaper on his skin. Sebastian watched on helplessly from the closet. He took extra care to make sure no dust lingered in the air yet his human was still suffering. He knew his human needed rest to get better but Ciel had trouble sleeping peacefully. _Maybe I could slip a tonic in his water? Maybe some herbs? He seems to be sensitive to a lot of things though. I can’t risk making him worse by him have an allergic reaction._ Sebastian slipped out of the closet, still in his shadow form as he crept closer to Ciel. _Sleep. Bed. The couple that was here a long time ago…when their child wasn’t feeling well or couldn’t sleep they would rock the child to sleep! I can do that!_ He grinned and smoked underneath the bed frame, only taking solid form when he was sure he was hidden under the bed. He was crumpled up and squished but it was worth it if it helped his human sleep. He set his powerful clawed hands on either side and jostled the bed. _Hmm, I don’t see how this helps. Humans are so strange._ Ciel attempted to sit up but fell back into the mattress when he lost his balance. He blinked his bright sapphire eyes in confusion.

“Is-is there an earthquake?” Ciel croaked out. He brought a hand up to his sore throat and coughed. He looked around the room, finding everything steady. Realization dawned on him that it was only the bed that was shaking erratically. “What the-ahhh!” he bolted off the bed nearly falling flat on his face. He stared wide eyed at the shaking bed, it hovered off the ground. He sat on the floor and rocked back and forth. “That’s-that’s it, I’ve completely lost my mind…” he started crying choking on his tears. Sebastian let the bed drop back down, he was puzzled. _This seemed to soothe the tiny human, why did this terrify him?_ “I don’t know if you’re real…i-if you are, please…just please stop,” he sobbed. “I’m sorry I took over your house, I-I can’t afford anywhere else…” he laid flat out on the hardwood floor. “I promise I’ll leave as soon as I can afford it. Just, just don’t hurt me.” Sebastian’s heart broke at the defeated pleas coming from Ciel. All he wanted was a companion and he pushed him away, scared him bad enough that he wanted to leave. He waited for Ciel to pass out on the floor before he shimmied out from under the bed. He retracted his claws as much as he could before he carefully lifted Ciel up and placed him back in bed. He pulled the sheet over him and kissed the top of his head.

“I’m sorry, friend,” he smoked back into the shadows and headed to the cellar, where he remained the rest of the night.

1.

Sebastian kept his distance as much as he could in the small house. Most days he spent in the cellar, too depressed to even try to do something nice for Ciel. The human continued to reject him and to watch Ciel but not interact with him hurt too much. _Maybe one day he will grow to accept me. I just don’t know what else to do. I tried to help when he needed it most. I gave him gifts. Yet all I do is frighten him. Humans are such strange creatures._

Ciel’s health was slightly better. His strength hadn’t fully returned and he still ran low fevers. He was finally sleeping again and hadn’t had any more run ins with what he dubbed ‘the ghost.’ He was curled up on the couch, lost in his favorite book. He didn’t even hear the kitchen window slide open. A dark figure snuck up behind him and gripped Ciel’s hair, pulling him up to stand. Ciel kicked a leg out and managed to push the coffee table enough that it squeaked across the floor the few inches it traveled. A knife pressed into his throat, blood beaded against the blade.

“Make a sound and I’ll slice your throat,” he yanked Ciel’s head back further so he could lock eyes with him. Ciel had to bite his tongue to stop from saying, _‘You already did slice it.’_ “You’re the old lady’s grandson right?” Ciel looked puzzled at the robber. “You must be, no one else in their right mind would move into this place alone. Tell me where the heirlooms are!”

Sebastian’s ears had perked up at the horrendous screech upstairs. He heard a voice he didn’t recognize, it sounded angry. His nostrils flared. _Blood? Ciel!_

“I-I don’t know what you’re talking about,” Ciel was roughly shoved to the ground. His head made contact and he saw stars.

“I don’t want to play games, tell me now and I’ll let you live,” he grabbed Ciel’s hair and repeatedly slammed his head against the floor. Ciel groaned pain blossomed behind his eyes as well as the rest of his head. The knife was pushed against his throat once more. “This is your last chance kid.”

“WHO DARES TO ATTACK MY HUMAN?” Sebastian’s voice echoed around the room. The temperature dramatically plummeted as light was blotted out; shadows danced and flickered to life. Sebastian brought a large clawed hand to the man’s throat and squeezed. “Vile being, you cross where you are not welcome. I know your intentions, I see the darkness in your heart. You reek of sin, blood has stained your soul. Of all your corruptions, your greed has been your undoing.”

“P-please! Sir! L-let me go!” the robber clawed at Sebastian’s hand frantically. Sebastian’s eyes burned bright. Red illuminating the robber’s terrified face. Sebastian cocked his head and smiled, flashing his multiple rows of sharp teeth.

“I cannot do that. I do not show mercy and you are far too late to seek redemption,” his tail sprung and pierced through the robber’s heart, killing him instantly. He let the body drop to the floor and stepped back into the darkest shadows. Ciel coughed and struggled to sit up. His eyes darted around the room, searching for his savior.

“Wait, don’t go!” Ciel reached a hand out. “T-thank you, you saved me!” Sebastian smiled sadly.

“Yes, it seems for once I’ve done something right,” he nodded.

“It-it’s you!” Ciel sputtered. “You’re real?”

“I must go,” Sebastian sighed.

“No! Let me, let me see you!” Ciel scrambled to get to his feet. “I know you never meant to hurt me, you’ve proven that to me just now.”

“Ciel, I don’t think that’s a good idea. I don’t want to frighten you.”

“Please,” he reached out to the shadows. A large black hand came out to hold his. His eyes widened but he stood firm. “What’s your name?” He stepped back, pulling the demon from his shadows. Slowly shiny black hooves emerged, limbs that seemed to go on for eternity covered in onyx with delicate white swirls followed. Ciel had to bend his neck to look up, blood lazily dripped from his fresh cut. A smile spread across the demon’s face. He bowed his head, four ebony horns shining proudly.

“I am Sebastian, it is nice to properly meet you, Ciel,” he brought Ciel’s small hand to his shiny black lips and kissed the delicate thing. Ciel blushed, though still unsure there was something charming about the demon.

“Likewise, Sebastian,” he gave a warm smile back to the demon, no Sebastian, he corrected himself. His new housemate.


End file.
